utils: networks

1 files changed, 181 insertions, 0 deletions

diff --git a/utils/networks/networks.go b/utils/networks/networks.go
new file mode 100644
index 0000000..328f006
--- /dev/null
+++ b/utils/networks/networks.go
@@ -0,0 +1,181 @@
+package networks
+
+import (
+	"cmp"
+	"fmt"
+	"log"
+	"net/netip"
+	"os"
+	"slices"
+	"utils/ipam/yaml_model"
+)
+
+func RunNetworks() error {
+	ipamYaml := "../ansible/group_vars/all/ipam.yml"
+	bs, err := os.ReadFile(ipamYaml)
+	if err != nil {
+		return err
+	}
+
+	ipam, err := loadIpam(bs)
+	if err != nil {
+		return err
+	}
+
+	networks := slices.SortedFunc(slices.Values(ipam.networks), CompareNetwork)
+	roots := slices.SortedFunc(slices.Values(ipam.FindRoots()), CompareNetwork)
+
+	fmt.Printf("digraph {\n")
+	//fmt.Printf(" layout=dot\n")
+	//fmt.Printf(" layout=twopi\n")
+	fmt.Printf(" layout=fdp\n")
+	//fmt.Printf(" layout=circo\n")
+	//fmt.Printf(" layout=neato\n")
+	//fmt.Printf(" ranksep=3\n")
+	//fmt.Printf(" ratio=auto\n")
+	//fmt.Printf(" rankdir=LR\n")
+	//fmt.Printf(" rankdir=RL\n")
+	fmt.Printf(" rankdir=TB\n")
+	//fmt.Printf(" sep=3\n")
+	//fmt.Printf(" overlap_scaling=-10\n")
+	fmt.Printf("node [len=10];")
+	fmt.Printf("node [shape=box];")
+	fmt.Printf("overlap=false")
+
+	fmt.Printf("\n")
+	fmt.Printf("  # Nodes\n")
+	for _, n := range networks {
+		fmt.Printf("  %s [ label = \"%s\\n%s\"];\n", n.name, n.name, n.prefix)
+	}
+
+	fmt.Printf("\n")
+	fmt.Printf("  # Roots\n")
+	for _, n := range roots {
+		fmt.Printf("  %s [ root = true ];\n", n.name)
+	}
+
+	fmt.Printf("\n")
+	fmt.Printf("  # Relationships\n")
+	for _, n := range networks {
+		for _, c := range ipam.networks {
+			if c.parent == n {
+				fmt.Printf("  %s -> %s", n.name, c.name)
+				fmt.Printf(";\n")
+			}
+		}
+	}
+	fmt.Printf("}\n")
+
+	return nil
+}
+
+func loadIpam(bs []byte) (*Ipam, error) {
+	parsed, err := yaml_model.Parse(bs)
+	if err != nil {
+		return nil, err
+	}
+
+	ipam_, err := processNetworks(parsed.Ipam6.Networks)
+	if err != nil {
+		return nil, err
+	}
+
+	ipam_.ResolveParents()
+
+	return ipam_, nil
+}
+
+type Ipam struct {
+	networks []*Network
+}
+
+func contains(a, b netip.Prefix) bool {
+	return b.Bits() > a.Bits() && b.Overlaps(a)
+}
+
+func (ipam *Ipam) ResolveParents() {
+	for _, n := range ipam.networks {
+		log.Printf("network %s/%s", n.name, n.prefix)
+		for _, p := range ipam.networks {
+			if n == p {
+				continue
+			}
+			log.Printf(" candidate %s/%s", p.name, p.prefix)
+			if contains(p.prefix, n.prefix) {
+				if n.parent == nil {
+					log.Printf(" found parent %s/%s", p.name, p.prefix)
+					n.parent = p
+				} else {
+					if n.parent.prefix.Bits() < p.prefix.Bits() {
+						log.Printf(" found better parent %s/%s", p.name, p.prefix)
+						n.parent = p
+					}
+				}
+			}
+		}
+	}
+
+	return
+}
+
+func (ipam *Ipam) FindRoots() []*Network {
+	var ns []*Network
+
+	for _, n := range ipam.networks {
+		if n.parent == nil {
+			ns = append(ns, n)
+		}
+	}
+
+	return ns
+}
+
+type Network struct {
+	name   string
+	parent *Network
+	prefix netip.Prefix
+	hosts  []networkHost
+}
+
+func CompareNetwork(a, b *Network) int {
+	return cmp.Compare(a.name, b.name)
+}
+
+func (n *Network) Compare(other *Network) int {
+	return cmp.Compare(n.name, other.name)
+}
+
+type networkHost struct {
+	name    string
+	address netip.Addr
+}
+
+func processNetworks(networks map[string]yaml_model.Network6Yaml) (*Ipam, error) {
+	var ns []*Network
+
+	for name, net := range networks {
+		log.Printf("Processing net %v\n", name)
+		prefix, err := netip.ParsePrefix(net.Range)
+		if err != nil {
+			return nil, fmt.Errorf("error parsing net range: %v", err)
+		}
+		log.Printf("prefix: %s", prefix.String())
+
+		n := Network{name: name, prefix: prefix}
+		for hostname, a := range net.Hosts {
+			addr, err := netip.ParseAddr(a)
+			if err != nil {
+				return nil, fmt.Errorf("network: %s, unable to parse host address %s", n.name, a)
+			}
+
+			n.hosts = append(n.hosts, networkHost{
+				name:    hostname,
+				address: addr,
+			})
+		}
+
+		ns = append(ns, &n)
+	}
+
+	return &Ipam{networks: ns}, nil
+}